A huge conflict may be brewing in the Middle East. This time, it is not about Iraq, Syria or Israel and Palestine. It is about the rivalry between Saudi Arabia and Iran, the region’s leading Sunni and Shia Muslim powers, and it could potentially suck in all the above countries, plus Russia and the US. The Trump administration has sent senior envoys to Riyadh and other capitals. Moscow is deeply involved. Last week, Emmanuel Macron made an urgent visit to Saudi Arabia. The French president, speaking for Europe, stressed the need for stability after Lebanon’s prime minister, Saad Hariri, precipitously resigned.

At this possibly critical turning point, where is Britain? The shameful answer is, nowhere to be seen. What is the UK, with its long experience of Middle Eastern affairs, doing to defuse this dangerous crisis or protect British interests and citizens? Not a lot. Instead, our incompetent foreign secretary, Boris Johnson, is busy losing a personal battle with Iran over his gross mishandling of the case of Nazanin Zaghari-Ratcliffe, the British-Iranian woman jailed in Tehran on fabricated charges. Johnson is not a serious person. He lacks the sense of responsibility and gravitas required for his job. Theresa May picked him because, after the Brexit referendum, she could not refuse him a senior post. He has repeatedly proved himself unworthy of the honour. May should show some teeth – and sack him.

The Johnson embarrassment, while acute, is but one of many unfortunate by-products of Britain’s biggest problem: Brexit. Divisive internal wrangling and endless navel gazing over Brexit are overshadowing almost everything in political life, to the detriment not only of Britain’s economic prospects and social cohesion but also its standing and influence in the world. May and her Crazy Gang cabinet appear not to grasp the dismaying extent to which the UK’s views are now dismissed, ignored and ridiculed on the international stage. It is not just inside the EU that bemusement, contempt and pity reign.

What is the world at large to make of a British leader who is so clueless and lacking in authority that a senior minister, Priti Patel, can parade around Israel like a prime minister-in-waiting, holding high-level talks and peddling controversial initiatives at a sensitive juncture, all apparently without her knowledge or agreement?

As Britain flounders under the baleful influence of a clique of Tory hard Brexiters, the diminution of its global reputation proceeds apace. We are in danger of becoming the incredible shrinking island, slowly sinking, flags flying, into North Atlantic mists. Recent comments by Wilbur Ross, the US commerce secretary, suggesting Britain must scrap key regulatory standards to secure a bilateral trade deal, show how potentially harmful are the Brexiters’ half-baked ideas about a future free trade paradise. Do they still believe Trump’s America, China or India will offer sweetheart deals at mates’ rates? Dream on. Bigger powers will ruthlessly exploit Britain’s growing, self-inflicted weakness and isolation. And the cost will be borne not by Tory wreckers but by those in Britain who can least afford it.

What has plainly shocked May and her band of blunderers is the contrasting strength shown by their European interlocutors. Attempts to sow division in EU ranks have failed miserably. Nearly nine months after the triggering of article 50, the bloc remains united behind its tougher-than-expected negotiating position. German businesses, including the car exporters that ministers such as Liam Fox predicted would cave in when faced by the loss of British markets, are grimly preparing for a hard Brexit. The French can hardly hide their glee as City of London firms move jobs and business to Paris. EU citizens, far from inundating our shores before the Brexit guillotine falls, are heading the other way in droves, denuding the NHS and care services of much-needed workers.

Yet what does May do? Friendless, directionless and panicking, she doubles down on a losing bet. How else to describe her insistence on a firm date – 29 March 2019 – for leaving the EU? May seems to think this will help get the EU withdrawal bill through parliament and strengthen her position in Brussels. More magical thinking. Her move echoes Nigel Farage’s silly “independence day” declaration and is every bit as fatuous. If the government’s inept handling of Brexit continues, 29 March will be no day of celebration. It will be the day the people of Britain are thrown off a cliff by their own leaders.

‘Britain has had a bellyful of Davis’s jejune blather. He has made a monumental mess of things. He should be replaced.’ Photograph: Anadolu Agency/Getty Images

May’s government is a chronic shambles. Even its Tory press supporters, looking at Westminster’s sexual harassment scandal and a likely budget row later this month, admit as much. But so, too, undeniably, are the Brexit negotiations. Last week’s talks, rather than forging consensus on issues of money, citizens’ rights and the Irish border, revealed widening differences. Michel Barnier, the EU negotiator, has now given Britain two weeks to find solutions. British and continental business groups say time is running out for arranging a transition deal, let alone the promised talks on an EU-UK trade pact. Yet there is David Davis, the Brexit “tsar”, again blithely claiming that progress is being made, while pleading for Europe’s political leaders to rescue him. Britain has had a bellyful of Davis’s jejune blather. He has made a monumental mess of things. He should be replaced.

A crisis point is looming and, if only to avoid total meltdown, it is time for a time-out on Brexit. It is time to stop the clock. Common sense demands it; the empirical evidence dictates it. This is not to say the decision to leave the EU should be reversed. This is not to say last year’s referendum result should be ignored. This is not to say that a second referendum should be held, although the case in favour, if and when an exit deal is agreed, is steadily strengthening. It is to say that the negotiations have reached an obvious, perilous impasse and may become disastrously counterproductive.

It is in Britain’s and Europe’s interest to set back the 2019 departure date to give more time and space to resolve outstanding issues. It is the government’s responsibility to halt the needless damage already being done to the living standards and life prospects of ordinary people. A Brexit freeze would allow both sides to step back and take stock. It would mitigate the damaging uncertainty affecting businesses and investors and open the way, perhaps, for a more realistic transition timetable. It would calm, for a while, the arguments over who owes what to whom.

The EU does not want a hard Brexit crash. Nor do most people in Britain, beyond the lunatic Tory fringe, as opinion polls indicate. There is no legal obstacle to delaying implementation of article 50, as its author, Lord Kerr, stated last week. If May truly believes respecting the democratic will is paramount, she must admit the negotiations have hit the buffers, accept she has no mandate to lead the country over a no-deal precipice and pause for a substantive rethink about what she is really trying to achieve. The national interest, and Britain’s future standing in the world, requires nothing less.